/*two_func.c -- 一个文件包含两个函数*/
#include<stdio.h>
void butler(void);
int main(void)
{
    printf("I will summon the butler function.\n");
    butler();
    printf("Yes.Bring me some tea and writeable DVDs.\n");
    return 0;
}
void butler(void)
{
    printf ("You rang,sir?\n");
}